Hyperactivity and Learning Deficits in Transgenic Mice Bearing a Human Mutant Thyroid Hormone β1 Receptor Gene

Resistance to thyroid hormone (RTH) is a human syndrome mapped to the thyroid receptor β (TRβ) gene on chromosome 3, representing a mutation of the ligandbinding domain of the TRβ gene. The syndrome is characterized by reduced tissue responsiveness to thyroid hormone and elevated serum levels of thyroid hormones. A common behavioral phenotype associated with RTH is attention deficit hyperactivity disorder (ADHD). To test the hypothesis that RTH produces attention deficits and/or hyperactivity, transgenic mice expressing a mutant TRβ gene were generated. The present experiment tested RTH transgenic mice from the PV kindred on behavioral tasks relevant to the primary features of ADHD: hyperactivity, sustained attention (vigilance), learning, and impulsivity. Male transgenic mice showed elevated locomotor activity in an open field compared to male wild-type littermate controls. Both male and female transgenic mice exhibited impaired learning of an autoshaping task, compared to wild-type controls. On a vigilance task in an operant chamber, there were no differences between transgenics and controls on the proportion of hits, response latency, or duration of stimulus tolerated. On an operant go/no-go task measuring sustained attention and impulsivity, there were no differences between controls and transgenics. These results indicate that transgenic mice bearing a mutant human TRβ gene demonstrate several behavioral characteristics of ADHD and may serve a valuable heuristic role in elucidating possible candidate genes in converging pathways for other causes of ADHD.     

Visual inertia of rotating 3-D objects

Five experiments were designed to determine whether a rotating, transparent 3-D cloud of dots (simulated sphere) could influence the perceived direction of rotation of a subsequent sphere. Experiment 1 established conditions under which the direction of rotation of a virtual sphere was perceived unambiguously. When a near-far luminance difference and perspective depth cues were present, observers consistently saw the sphere rotate in the intended direction. In Experiment 2, a near-far luminance difference was used to create an unambiguous rotation sequence that was followed by a directionally ambiguous rotation sequence that lacked both the near-far luminance cue and the perspective cue. Observers consistently saw the second sequence as rotating in the same direction as the first, indicating the presence of 3-D visual inertia. Experiment 3 showed that 3-D visual inertia was sufficiently powerful to bias the perceived direction of a rotation sequence made unambiguous by a near-far luminance cue. Experiment 5 showed that 3-D visual inertia could be obtained using an occlusion depth cue to create an unambiguous inertia-inducing sequence. Finally, Experiments 2, 4, and 5 all revealed a fast-decay phase of inertia that lasted for approximately 800 msec, followed by an asymptotic phase that lasted for periods as long as 1,600 msec. The implications of these findings are examined with respect to motion mechanisms of 3-D visual inertia.     

GENERALITY AND SIDE EFFECTS OF OVERCORRECTION1

The effects and side effects of overcorrection for self-stimulatory behaviors of two children in a specialized day-care program were evaluated. For one child, a “hand” overcorrection procedure involving arm and hand exercises was introduced contingent upon inappropriate hand movements and later contingent upon inappropriate foot movements. After “hand” overcorrection was withdrawn for inappropriate foot movements, a “foot” overcorrection procedure involving foot and leg exercises was introduced contingent upon inappropriate foot movements. For a second child, the “hand” overcorrection procedure was introduced contingent upon inappropriate hand movements during a free-play period, and later contingent upon inappropriate vocalizations at naptime. “Hand” overcorrection was withdrawn and then re-introduced sequentially for both behaviors. Several concurrent behaviors were measured to assess multiple effects of treatment. Results for both children indicated the “hand” overcorrection procedure suppressed inappropriate hand movements and inappropriate behaviors that were topographically dissimilar. In addition, inverse relationships were observed between the second child's inappropriate hand movements and appropriate toy usage during free play and between his inappropriate vocalizations and inappropriate foot movements during naptime. Results suggest that overcorrection procedures that are effective for one behavior can be used to reduce the frequency of topographically different behaviors. This finding is discussed in terms of its practical implications for therapists.     

Authoritarianism and job preference

The hypothesis tested was that authoritarian personalities prefer the natural sciences (specifically biology and chemistry) and nonauthoritarian personalities choose the social sciences and humanities (specifically, psychology and philosophy). The results strongly supported the hypothesis. Since the study was conducted on freshmen students in Israel who select their department at the time they apply for admission to the university, the results were interpreted as indicating that authoritarians choose professions different from nonauthoritarians.     

The role of nonlinguistic stimuli and semantic relations in children's acquisition of grammatical utterances

Eighteen children, randomly assigned to one of six conditions, were trained in the use of two-word subject-verb (e.g. “mommy go”) utterances. The groups differed in (1) the number of different semantic relations theoretically underlying the subject-verb utterances on which the children were trained, and (2) the extent to which these semantic relations were associated with nonlinguistic events. The results indicated that the children acquired the subject-verb utterance forms more readily when they were also exposed to the events to which the utterances actually referred. Provided that the subject-verb utterances were related to ongoing events, the number of relations “underlying” these utterances did not appear critical. These results suggest that the child's acquisition of novel and grammatical utterances describing nonlinguistic stimuli highly similar to those in his natural environment are amenable to experimental control.     

Effect on College Choice Satisfaction of Matching Students and Colleges

The purpose of this study was to test the currently held theory of homogeneous matching of a student to a college and its effect on college choice satisfaction. Measures of scholastic potential, personality, and interest, and subcultural orientation on 7,257 freshmen enrolled in 28 colleges were related to their expressions of satisfaction with their choice of college. The contention that students most similar or dissimilar to students at their chosen school would be most satisfied or dissatisfied was not supported. The relationship between satisfaction and matching is minimal and quite complex and casts serious doubt on this form of placing students in college.